arch/powerpc/platforms/powernv/opal-dump.c - maze/linux - Git at Google

 /*
  * PowerNV OPAL Dump Interface
  *
  * Copyright 2013,2014 IBM Corp.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  */

 #include <linux/kobject.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/pagemap.h>
 #include <linux/delay.h>

 #include <asm/opal.h>

 #define DUMP_TYPE_FSP	0x01

 struct dump_obj {
 	struct kobject  kobj;
 	struct bin_attribute dump_attr;
 	uint32_t	id;  /* becomes object name */
 	uint32_t	type;
 	uint32_t	size;
 	char		*buffer;
 };
 #define to_dump_obj(x) container_of(x, struct dump_obj, kobj)

 struct dump_attribute {
 	struct attribute attr;
 	ssize_t (*show)(struct dump_obj *dump, struct dump_attribute *attr,
 			char *buf);
 	ssize_t (*store)(struct dump_obj *dump, struct dump_attribute *attr,
 			 const char *buf, size_t count);
 };
 #define to_dump_attr(x) container_of(x, struct dump_attribute, attr)

 static ssize_t dump_id_show(struct dump_obj *dump_obj,
 			    struct dump_attribute *attr,
 			    char *buf)
 {
 	return sprintf(buf, "0x%x\n", dump_obj->id);
 }

 static const char* dump_type_to_string(uint32_t type)
 {
 	switch (type) {
 	case 0x01: return "SP Dump";
 	case 0x02: return "System/Platform Dump";
 	case 0x03: return "SMA Dump";
 	default: return "unknown";
 	}
 }

 static ssize_t dump_type_show(struct dump_obj *dump_obj,
 			      struct dump_attribute *attr,
 			      char *buf)
 {

 	return sprintf(buf, "0x%x %s\n", dump_obj->type,
 		       dump_type_to_string(dump_obj->type));
 }

 static ssize_t dump_ack_show(struct dump_obj *dump_obj,
 			     struct dump_attribute *attr,
 			     char *buf)
 {
 	return sprintf(buf, "ack - acknowledge dump\n");
 }

 /*
  * Send acknowledgement to OPAL
  */
 static int64_t dump_send_ack(uint32_t dump_id)
 {
 	int rc;

 	rc = opal_dump_ack(dump_id);
 	if (rc)
 		pr_warn("%s: Failed to send ack to Dump ID 0x%x (%d)\n",
 			__func__, dump_id, rc);
 	return rc;
 }

 static ssize_t dump_ack_store(struct dump_obj *dump_obj,
 			      struct dump_attribute *attr,
 			      const char *buf,
 			      size_t count)
 {
 	dump_send_ack(dump_obj->id);
 	sysfs_remove_file_self(&dump_obj->kobj, &attr->attr);
 	kobject_put(&dump_obj->kobj);
 	return count;
 }

 /* Attributes of a dump
  * The binary attribute of the dump itself is dynamic
  * due to the dynamic size of the dump
  */
 static struct dump_attribute id_attribute =
 	__ATTR(id, 0666, dump_id_show, NULL);
 static struct dump_attribute type_attribute =
 	__ATTR(type, 0666, dump_type_show, NULL);
 static struct dump_attribute ack_attribute =
 	__ATTR(acknowledge, 0660, dump_ack_show, dump_ack_store);

 static ssize_t init_dump_show(struct dump_obj *dump_obj,
 			      struct dump_attribute *attr,
 			      char *buf)
 {
 	return sprintf(buf, "1 - initiate dump\n");
 }

 static int64_t dump_fips_init(uint8_t type)
 {
 	int rc;

 	rc = opal_dump_init(type);
 	if (rc)
 		pr_warn("%s: Failed to initiate FipS dump (%d)\n",
 			__func__, rc);
 	return rc;
 }

 static ssize_t init_dump_store(struct dump_obj *dump_obj,
 			       struct dump_attribute *attr,
 			       const char *buf,
 			       size_t count)
 {
 	dump_fips_init(DUMP_TYPE_FSP);
 	pr_info("%s: Initiated FSP dump\n", __func__);
 	return count;
 }

 static struct dump_attribute initiate_attribute =
 	__ATTR(initiate_dump, 0600, init_dump_show, init_dump_store);

 static struct attribute *initiate_attrs[] = {
 	&initiate_attribute.attr,
 	NULL,
 };

 static struct attribute_group initiate_attr_group = {
 	.attrs = initiate_attrs,
 };

 static struct kset *dump_kset;

 static ssize_t dump_attr_show(struct kobject *kobj,
 			      struct attribute *attr,
 			      char *buf)
 {
 	struct dump_attribute *attribute;
 	struct dump_obj *dump;

 	attribute = to_dump_attr(attr);
 	dump = to_dump_obj(kobj);

 	if (!attribute->show)
 		return -EIO;

 	return attribute->show(dump, attribute, buf);
 }

 static ssize_t dump_attr_store(struct kobject *kobj,
 			       struct attribute *attr,
 			       const char *buf, size_t len)
 {
 	struct dump_attribute *attribute;
 	struct dump_obj *dump;

 	attribute = to_dump_attr(attr);
 	dump = to_dump_obj(kobj);

 	if (!attribute->store)
 		return -EIO;

 	return attribute->store(dump, attribute, buf, len);
 }

 static const struct sysfs_ops dump_sysfs_ops = {
 	.show = dump_attr_show,
 	.store = dump_attr_store,
 };

 static void dump_release(struct kobject *kobj)
 {
 	struct dump_obj *dump;

 	dump = to_dump_obj(kobj);
 	vfree(dump->buffer);
 	kfree(dump);
 }

 static struct attribute *dump_default_attrs[] = {
 	&id_attribute.attr,
 	&type_attribute.attr,
 	&ack_attribute.attr,
 	NULL,
 };

 static struct kobj_type dump_ktype = {
 	.sysfs_ops = &dump_sysfs_ops,
 	.release = &dump_release,
 	.default_attrs = dump_default_attrs,
 };

 static void free_dump_sg_list(struct opal_sg_list *list)
 {
 	struct opal_sg_list *sg1;
 	while (list) {
 		sg1 = list->next;
 		kfree(list);
 		list = sg1;
 	}
 	list = NULL;
 }

 static struct opal_sg_list *dump_data_to_sglist(struct dump_obj *dump)
 {
 	struct opal_sg_list *sg1, *list = NULL;
 	void *addr;
 	int64_t size;

 	addr = dump->buffer;
 	size = dump->size;

 	sg1 = kzalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!sg1)
 		goto nomem;

 	list = sg1;
 	sg1->num_entries = 0;
 	while (size > 0) {
 		/* Translate virtual address to physical address */
 		sg1->entry[sg1->num_entries].data =
 			(void *)(vmalloc_to_pfn(addr) << PAGE_SHIFT);

 		if (size > PAGE_SIZE)
 			sg1->entry[sg1->num_entries].length = PAGE_SIZE;
 		else
 			sg1->entry[sg1->num_entries].length = size;

 		sg1->num_entries++;
 		if (sg1->num_entries >= SG_ENTRIES_PER_NODE) {
 			sg1->next = kzalloc(PAGE_SIZE, GFP_KERNEL);
 			if (!sg1->next)
 				goto nomem;

 			sg1 = sg1->next;
 			sg1->num_entries = 0;
 		}
 		addr += PAGE_SIZE;
 		size -= PAGE_SIZE;
 	}
 	return list;

 nomem:
 	pr_err("%s : Failed to allocate memory\n", __func__);
 	free_dump_sg_list(list);
 	return NULL;
 }

 static void sglist_to_phy_addr(struct opal_sg_list *list)
 {
 	struct opal_sg_list *sg, *next;

 	for (sg = list; sg; sg = next) {
 		next = sg->next;
 		/* Don't translate NULL pointer for last entry */
 		if (sg->next)
 			sg->next = (struct opal_sg_list *)__pa(sg->next);
 		else
 			sg->next = NULL;

 		/* Convert num_entries to length */
 		sg->num_entries =
 			sg->num_entries * sizeof(struct opal_sg_entry) + 16;
 	}
 }

 static int64_t dump_read_info(uint32_t *id, uint32_t *size, uint32_t *type)
 {
 	int rc;
 	*type = 0xffffffff;

 	rc = opal_dump_info2(id, size, type);

 	if (rc == OPAL_PARAMETER)
 		rc = opal_dump_info(id, size);

 	if (rc)
 		pr_warn("%s: Failed to get dump info (%d)\n",
 			__func__, rc);
 	return rc;
 }

 static int64_t dump_read_data(struct dump_obj *dump)
 {
 	struct opal_sg_list *list;
 	uint64_t addr;
 	int64_t rc;

 	/* Allocate memory */
 	dump->buffer = vzalloc(PAGE_ALIGN(dump->size));
 	if (!dump->buffer) {
 		pr_err("%s : Failed to allocate memory\n", __func__);
 		rc = -ENOMEM;
 		goto out;
 	}

 	/* Generate SG list */
 	list = dump_data_to_sglist(dump);
 	if (!list) {
 		rc = -ENOMEM;
 		goto out;
 	}

 	/* Translate sg list addr to real address */
 	sglist_to_phy_addr(list);

 	/* First entry address */
 	addr = __pa(list);

 	/* Fetch data */
 	rc = OPAL_BUSY_EVENT;
 	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
 		rc = opal_dump_read(dump->id, addr);
 		if (rc == OPAL_BUSY_EVENT) {
 			opal_poll_events(NULL);
 			msleep(20);
 		}
 	}

 	if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL)
 		pr_warn("%s: Extract dump failed for ID 0x%x\n",
 			__func__, dump->id);

 	/* Free SG list */
 	free_dump_sg_list(list);

 out:
 	return rc;
 }

 static ssize_t dump_attr_read(struct file *filep, struct kobject *kobj,
 			      struct bin_attribute *bin_attr,
 			      char *buffer, loff_t pos, size_t count)
 {
 	ssize_t rc;

 	struct dump_obj *dump = to_dump_obj(kobj);

 	if (!dump->buffer) {
 		rc = dump_read_data(dump);

 		if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL) {
 			vfree(dump->buffer);
 			dump->buffer = NULL;

 			return -EIO;
 		}
 		if (rc == OPAL_PARTIAL) {
 			/* On a partial read, we just return EIO
 			 * and rely on userspace to ask us to try
 			 * again.
 			 */
 			pr_info("%s: Platform dump partially read.ID = 0x%x\n",
 				__func__, dump->id);
 			return -EIO;
 		}
 	}

 	memcpy(buffer, dump->buffer + pos, count);

 	/* You may think we could free the dump buffer now and retrieve
 	 * it again later if needed, but due to current firmware limitation,
 	 * that's not the case. So, once read into userspace once,
 	 * we keep the dump around until it's acknowledged by userspace.
 	 */

 	return count;
 }

 static struct dump_obj *create_dump_obj(uint32_t id, size_t size,
 					uint32_t type)
 {
 	struct dump_obj *dump;
 	int rc;

 	dump = kzalloc(sizeof(*dump), GFP_KERNEL);
 	if (!dump)
 		return NULL;

 	dump->kobj.kset = dump_kset;

 	kobject_init(&dump->kobj, &dump_ktype);

 	sysfs_bin_attr_init(&dump->dump_attr);

 	dump->dump_attr.attr.name = "dump";
 	dump->dump_attr.attr.mode = 0400;
 	dump->dump_attr.size = size;
 	dump->dump_attr.read = dump_attr_read;

 	dump->id = id;
 	dump->size = size;
 	dump->type = type;

 	rc = kobject_add(&dump->kobj, NULL, "0x%x-0x%x", type, id);
 	if (rc) {
 		kobject_put(&dump->kobj);
 		return NULL;
 	}

 	rc = sysfs_create_bin_file(&dump->kobj, &dump->dump_attr);
 	if (rc) {
 		kobject_put(&dump->kobj);
 		return NULL;
 	}

 	pr_info("%s: New platform dump. ID = 0x%x Size %u\n",
 		__func__, dump->id, dump->size);

 	kobject_uevent(&dump->kobj, KOBJ_ADD);

 	return dump;
 }

 static int process_dump(void)
 {
 	int rc;
 	uint32_t dump_id, dump_size, dump_type;
 	struct dump_obj *dump;
 	char name[22];

 	rc = dump_read_info(&dump_id, &dump_size, &dump_type);
 	if (rc != OPAL_SUCCESS)
 		return rc;

 	sprintf(name, "0x%x-0x%x", dump_type, dump_id);

 	/* we may get notified twice, let's handle
 	 * that gracefully and not create two conflicting
 	 * entries.
 	 */
 	if (kset_find_obj(dump_kset, name))
 		return 0;

 	dump = create_dump_obj(dump_id, dump_size, dump_type);
 	if (!dump)
 		return -1;

 	return 0;
 }

 static void dump_work_fn(struct work_struct *work)
 {
 	process_dump();
 }

 static DECLARE_WORK(dump_work, dump_work_fn);

 static void schedule_process_dump(void)
 {
 	schedule_work(&dump_work);
 }

 /*
  * New dump available notification
  *
  * Once we get notification, we add sysfs entries for it.
  * We only fetch the dump on demand, and create sysfs asynchronously.
  */
 static int dump_event(struct notifier_block *nb,
 		      unsigned long events, void *change)
 {
 	if (events & OPAL_EVENT_DUMP_AVAIL)
 		schedule_process_dump();

 	return 0;
 }

 static struct notifier_block dump_nb = {
 	.notifier_call  = dump_event,
 	.next           = NULL,
 	.priority       = 0
 };

 void __init opal_platform_dump_init(void)
 {
 	int rc;

 	dump_kset = kset_create_and_add("dump", NULL, opal_kobj);
 	if (!dump_kset) {
 		pr_warn("%s: Failed to create dump kset\n", __func__);
 		return;
 	}

 	rc = sysfs_create_group(&dump_kset->kobj, &initiate_attr_group);
 	if (rc) {
 		pr_warn("%s: Failed to create initiate dump attr group\n",
 			__func__);
 		kobject_put(&dump_kset->kobj);
 		return;
 	}

 	rc = opal_notifier_register(&dump_nb);
 	if (rc) {
 		pr_warn("%s: Can't register OPAL event notifier (%d)\n",
 			__func__, rc);
 		return;
 	}

 	opal_dump_resend_notification();
 }
	/*
	* PowerNV OPAL Dump Interface
	*
	* Copyright 2013,2014 IBM Corp.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*/

	#include <linux/kobject.h>
	#include <linux/mm.h>
	#include <linux/slab.h>
	#include <linux/vmalloc.h>
	#include <linux/pagemap.h>
	#include <linux/delay.h>

	#include <asm/opal.h>

	#define DUMP_TYPE_FSP 0x01

	struct dump_obj {
	struct kobject kobj;
	struct bin_attribute dump_attr;
	uint32_t id; /* becomes object name */
	uint32_t type;
	uint32_t size;
	char *buffer;
	};
	#define to_dump_obj(x) container_of(x, struct dump_obj, kobj)

	struct dump_attribute {
	struct attribute attr;
	ssize_t (show)(struct dump_obj dump, struct dump_attribute *attr,
	char *buf);
	ssize_t (store)(struct dump_obj dump, struct dump_attribute *attr,
	const char *buf, size_t count);
	};
	#define to_dump_attr(x) container_of(x, struct dump_attribute, attr)

	static ssize_t dump_id_show(struct dump_obj *dump_obj,
	struct dump_attribute *attr,
	char *buf)
	{
	return sprintf(buf, "0x%x\n", dump_obj->id);
	}

	static const char* dump_type_to_string(uint32_t type)
	{
	switch (type) {
	case 0x01: return "SP Dump";
	case 0x02: return "System/Platform Dump";
	case 0x03: return "SMA Dump";
	default: return "unknown";
	}
	}

	static ssize_t dump_type_show(struct dump_obj *dump_obj,
	struct dump_attribute *attr,
	char *buf)
	{

	return sprintf(buf, "0x%x %s\n", dump_obj->type,
	dump_type_to_string(dump_obj->type));
	}

	static ssize_t dump_ack_show(struct dump_obj *dump_obj,
	struct dump_attribute *attr,
	char *buf)
	{
	return sprintf(buf, "ack - acknowledge dump\n");
	}

	/*
	* Send acknowledgement to OPAL
	*/
	static int64_t dump_send_ack(uint32_t dump_id)
	{
	int rc;

	rc = opal_dump_ack(dump_id);
	if (rc)
	pr_warn("%s: Failed to send ack to Dump ID 0x%x (%d)\n",
	__func__, dump_id, rc);
	return rc;
	}

	static ssize_t dump_ack_store(struct dump_obj *dump_obj,
	struct dump_attribute *attr,
	const char *buf,
	size_t count)
	{
	dump_send_ack(dump_obj->id);
	sysfs_remove_file_self(&dump_obj->kobj, &attr->attr);
	kobject_put(&dump_obj->kobj);
	return count;
	}

	/* Attributes of a dump
	* The binary attribute of the dump itself is dynamic
	* due to the dynamic size of the dump
	*/
	static struct dump_attribute id_attribute =
	__ATTR(id, 0666, dump_id_show, NULL);
	static struct dump_attribute type_attribute =
	__ATTR(type, 0666, dump_type_show, NULL);
	static struct dump_attribute ack_attribute =
	__ATTR(acknowledge, 0660, dump_ack_show, dump_ack_store);

	static ssize_t init_dump_show(struct dump_obj *dump_obj,
	struct dump_attribute *attr,
	char *buf)
	{
	return sprintf(buf, "1 - initiate dump\n");
	}

	static int64_t dump_fips_init(uint8_t type)
	{
	int rc;

	rc = opal_dump_init(type);
	if (rc)
	pr_warn("%s: Failed to initiate FipS dump (%d)\n",
	__func__, rc);
	return rc;
	}

	static ssize_t init_dump_store(struct dump_obj *dump_obj,
	struct dump_attribute *attr,
	const char *buf,
	size_t count)
	{
	dump_fips_init(DUMP_TYPE_FSP);
	pr_info("%s: Initiated FSP dump\n", __func__);
	return count;
	}

	static struct dump_attribute initiate_attribute =
	__ATTR(initiate_dump, 0600, init_dump_show, init_dump_store);

	static struct attribute *initiate_attrs[] = {
	&initiate_attribute.attr,
	NULL,
	};

	static struct attribute_group initiate_attr_group = {
	.attrs = initiate_attrs,
	};

	static struct kset *dump_kset;

	static ssize_t dump_attr_show(struct kobject *kobj,
	struct attribute *attr,
	char *buf)
	{
	struct dump_attribute *attribute;
	struct dump_obj *dump;

	attribute = to_dump_attr(attr);
	dump = to_dump_obj(kobj);

	if (!attribute->show)
	return -EIO;

	return attribute->show(dump, attribute, buf);
	}

	static ssize_t dump_attr_store(struct kobject *kobj,
	struct attribute *attr,
	const char *buf, size_t len)
	{
	struct dump_attribute *attribute;
	struct dump_obj *dump;

	attribute = to_dump_attr(attr);
	dump = to_dump_obj(kobj);

	if (!attribute->store)
	return -EIO;

	return attribute->store(dump, attribute, buf, len);
	}

	static const struct sysfs_ops dump_sysfs_ops = {
	.show = dump_attr_show,
	.store = dump_attr_store,
	};

	static void dump_release(struct kobject *kobj)
	{
	struct dump_obj *dump;

	dump = to_dump_obj(kobj);
	vfree(dump->buffer);
	kfree(dump);
	}

	static struct attribute *dump_default_attrs[] = {
	&id_attribute.attr,
	&type_attribute.attr,
	&ack_attribute.attr,
	NULL,
	};

	static struct kobj_type dump_ktype = {
	.sysfs_ops = &dump_sysfs_ops,
	.release = &dump_release,
	.default_attrs = dump_default_attrs,
	};

	static void free_dump_sg_list(struct opal_sg_list *list)
	{
	struct opal_sg_list *sg1;
	while (list) {
	sg1 = list->next;
	kfree(list);
	list = sg1;
	}
	list = NULL;
	}

	static struct opal_sg_list dump_data_to_sglist(struct dump_obj dump)
	{
	struct opal_sg_list sg1, list = NULL;
	void *addr;
	int64_t size;

	addr = dump->buffer;
	size = dump->size;

	sg1 = kzalloc(PAGE_SIZE, GFP_KERNEL);
	if (!sg1)
	goto nomem;

	list = sg1;
	sg1->num_entries = 0;
	while (size > 0) {
	/* Translate virtual address to physical address */
	sg1->entry[sg1->num_entries].data =
	(void *)(vmalloc_to_pfn(addr) << PAGE_SHIFT);

	if (size > PAGE_SIZE)
	sg1->entry[sg1->num_entries].length = PAGE_SIZE;
	else
	sg1->entry[sg1->num_entries].length = size;

	sg1->num_entries++;
	if (sg1->num_entries >= SG_ENTRIES_PER_NODE) {
	sg1->next = kzalloc(PAGE_SIZE, GFP_KERNEL);
	if (!sg1->next)
	goto nomem;

	sg1 = sg1->next;
	sg1->num_entries = 0;
	}
	addr += PAGE_SIZE;
	size -= PAGE_SIZE;
	}
	return list;

	nomem:
	pr_err("%s : Failed to allocate memory\n", __func__);
	free_dump_sg_list(list);
	return NULL;
	}

	static void sglist_to_phy_addr(struct opal_sg_list *list)
	{
	struct opal_sg_list sg, next;

	for (sg = list; sg; sg = next) {
	next = sg->next;
	/* Don't translate NULL pointer for last entry */
	if (sg->next)
	sg->next = (struct opal_sg_list *)__pa(sg->next);
	else
	sg->next = NULL;

	/* Convert num_entries to length */
	sg->num_entries =
	sg->num_entries * sizeof(struct opal_sg_entry) + 16;
	}
	}

	static int64_t dump_read_info(uint32_t id, uint32_t size, uint32_t *type)
	{
	int rc;
	*type = 0xffffffff;

	rc = opal_dump_info2(id, size, type);

	if (rc == OPAL_PARAMETER)
	rc = opal_dump_info(id, size);

	if (rc)
	pr_warn("%s: Failed to get dump info (%d)\n",
	__func__, rc);
	return rc;
	}

	static int64_t dump_read_data(struct dump_obj *dump)
	{
	struct opal_sg_list *list;
	uint64_t addr;
	int64_t rc;

	/* Allocate memory */
	dump->buffer = vzalloc(PAGE_ALIGN(dump->size));
	if (!dump->buffer) {
	pr_err("%s : Failed to allocate memory\n", __func__);
	rc = -ENOMEM;
	goto out;
	}

	/* Generate SG list */
	list = dump_data_to_sglist(dump);
	if (!list) {
	rc = -ENOMEM;
	goto out;
	}

	/* Translate sg list addr to real address */
	sglist_to_phy_addr(list);

	/* First entry address */
	addr = __pa(list);

	/* Fetch data */
	rc = OPAL_BUSY_EVENT;
	while (rc == OPAL_BUSY \|\| rc == OPAL_BUSY_EVENT) {
	rc = opal_dump_read(dump->id, addr);
	if (rc == OPAL_BUSY_EVENT) {
	opal_poll_events(NULL);
	msleep(20);
	}
	}

	if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL)
	pr_warn("%s: Extract dump failed for ID 0x%x\n",
	__func__, dump->id);

	/* Free SG list */
	free_dump_sg_list(list);

	out:
	return rc;
	}

	static ssize_t dump_attr_read(struct file filep, struct kobject kobj,
	struct bin_attribute *bin_attr,
	char *buffer, loff_t pos, size_t count)
	{
	ssize_t rc;

	struct dump_obj *dump = to_dump_obj(kobj);

	if (!dump->buffer) {
	rc = dump_read_data(dump);

	if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL) {
	vfree(dump->buffer);
	dump->buffer = NULL;

	return -EIO;
	}
	if (rc == OPAL_PARTIAL) {
	/* On a partial read, we just return EIO
	* and rely on userspace to ask us to try
	* again.
	*/
	pr_info("%s: Platform dump partially read.ID = 0x%x\n",
	__func__, dump->id);
	return -EIO;
	}
	}

	memcpy(buffer, dump->buffer + pos, count);

	/* You may think we could free the dump buffer now and retrieve
	* it again later if needed, but due to current firmware limitation,
	* that's not the case. So, once read into userspace once,
	* we keep the dump around until it's acknowledged by userspace.
	*/

	return count;
	}

	static struct dump_obj *create_dump_obj(uint32_t id, size_t size,
	uint32_t type)
	{
	struct dump_obj *dump;
	int rc;

	dump = kzalloc(sizeof(*dump), GFP_KERNEL);
	if (!dump)
	return NULL;

	dump->kobj.kset = dump_kset;

	kobject_init(&dump->kobj, &dump_ktype);

	sysfs_bin_attr_init(&dump->dump_attr);

	dump->dump_attr.attr.name = "dump";
	dump->dump_attr.attr.mode = 0400;
	dump->dump_attr.size = size;
	dump->dump_attr.read = dump_attr_read;

	dump->id = id;
	dump->size = size;
	dump->type = type;

	rc = kobject_add(&dump->kobj, NULL, "0x%x-0x%x", type, id);
	if (rc) {
	kobject_put(&dump->kobj);
	return NULL;
	}

	rc = sysfs_create_bin_file(&dump->kobj, &dump->dump_attr);
	if (rc) {
	kobject_put(&dump->kobj);
	return NULL;
	}

	pr_info("%s: New platform dump. ID = 0x%x Size %u\n",
	__func__, dump->id, dump->size);

	kobject_uevent(&dump->kobj, KOBJ_ADD);

	return dump;
	}

	static int process_dump(void)
	{
	int rc;
	uint32_t dump_id, dump_size, dump_type;
	struct dump_obj *dump;
	char name[22];

	rc = dump_read_info(&dump_id, &dump_size, &dump_type);
	if (rc != OPAL_SUCCESS)
	return rc;

	sprintf(name, "0x%x-0x%x", dump_type, dump_id);

	/* we may get notified twice, let's handle
	* that gracefully and not create two conflicting
	* entries.
	*/
	if (kset_find_obj(dump_kset, name))
	return 0;

	dump = create_dump_obj(dump_id, dump_size, dump_type);
	if (!dump)
	return -1;

	return 0;
	}

	static void dump_work_fn(struct work_struct *work)
	{
	process_dump();
	}

	static DECLARE_WORK(dump_work, dump_work_fn);

	static void schedule_process_dump(void)
	{
	schedule_work(&dump_work);
	}

	/*
	* New dump available notification
	*
	* Once we get notification, we add sysfs entries for it.
	* We only fetch the dump on demand, and create sysfs asynchronously.
	*/
	static int dump_event(struct notifier_block *nb,
	unsigned long events, void *change)
	{
	if (events & OPAL_EVENT_DUMP_AVAIL)
	schedule_process_dump();

	return 0;
	}

	static struct notifier_block dump_nb = {
	.notifier_call = dump_event,
	.next = NULL,
	.priority = 0
	};

	void __init opal_platform_dump_init(void)
	{
	int rc;

	dump_kset = kset_create_and_add("dump", NULL, opal_kobj);
	if (!dump_kset) {
	pr_warn("%s: Failed to create dump kset\n", __func__);
	return;
	}

	rc = sysfs_create_group(&dump_kset->kobj, &initiate_attr_group);
	if (rc) {
	pr_warn("%s: Failed to create initiate dump attr group\n",
	__func__);
	kobject_put(&dump_kset->kobj);
	return;
	}

	rc = opal_notifier_register(&dump_nb);
	if (rc) {
	pr_warn("%s: Can't register OPAL event notifier (%d)\n",
	__func__, rc);
	return;
	}

	opal_dump_resend_notification();
	}